How to fuel up before you work out

If you've resolved to amp up (or start up) exercise in the new year, you might be wondering how to optimally fuel your workouts.

For advice on the best foods to eat before lacing up and heading to the gym or park, I spoke to Nancy Clark, MS, RD, whose Sports Nutrition Guidebook was released in its fifth edition last October. While Clark stresses that the best pre-workout foods vary from person to person and are affected by variety of other factors (including the intensity and duration of your workout), there are some general guidelines to keep in mind:

Consider Your Last Meal: If you've eaten a healthy, balanced meal a few hours before exercise (or even if you had a substantial dinner the night before), Clark says you might not need to eat anything before your workout--especially if it's a regular gym session or jog of an hour or less at a moderate intensity (a pace you could maintain for more than 30 minutes, says Clark).

Aim for 100 to 200 Calories: If you are working out in the morning or it's been a long time since your last meal, you'll probably want to give your blood sugar a little boost (your body also draws fuel from the glycogen stored in your muscles, so you don't need ot get all your energy from your blood sugar). Clark says about 100 to 200 calories should do the trick for the average workout.

Keep It Light: Remember our suggestions for Foods That Make You Feel Full? Well, disregard it if you're about to workout, especially if you're running, taking an aerobics class, or doing other jostling exercises. You want foods that sit well and digest easily. That means foods that contain simple carbs and that are low in fiber, fat, and protein. Good bets include a banana, a piece of a bagel, pretzels, half an English muffin, and dry cereal, says Clark.

Experiment: When it comes to how much fiber, fat, and protein, and how much food in general you can eat before exercise without feeling overloaded or having gastrointestinal distress, "each person is an experiment of one," says Clark. "You have to learn what works for your body, how much you can tolerate, and what foods settle best." You might find you can add a little nut butter, cheese, turkey, or avocado to that English muffin or some low-fat yogurt or milk to your cereal.

Look to Real Foods: While energy bars and drinks are convenient, Clark says there are plenty of naturally energizing foods. In addition to those mentioned above, you might want to give dried fruit (dates, raisins, dried pineapple, dried apples) a try. In fact, raisins are better than gels for pre-workout fueling, according to Men's Health. And remember that sports drinks are best consumed during intense, longer workouts not before exercise (you generally don't need them for efforts under an hour).

Know When to Eat More: If your stomach is already growling and you have at least an hour before your workout to digest, step it up from the suggestions above and have a small meal with a bit of protein, healthy fat, and carbs. Try a half a turkey or peanut butter sandwich, a smoothie, or a small portion of leftovers, or any of the suggestions in our article on Eating for Energy. Runner's World also has some great ideas for Prerun Mini Meals.